Lens grinding



G. S. DEY.

LENS GRINDING.

APPLICATION men MAR; e. 1920.

. Patented Dec. 5, 1922.

(7' .E INVENTOR I17 G/LBERTS. DEK

ATTORNEYS Patented Dec. 5, 1922.

umrno stares rare Lana caries.

GII BERT S. DEY, OF SOUTHBRITDGE, MASSACHUSETTS, ASSIGNOR T AMERICAN OPTICAL COMPANY, OF ASSOCIATION OF MASSACHUSETTS.

SOUTI-IBRIDGE, MASSACHUSETTS, A VOLUNTARY LENS GRINDING.

Application filed March 8, 1920.

To all whom z'trmcay concern:

Be it known that I, GILBERT S. DEY, a citizen of the United States, residing at Southbridge, in the county of Worcester and State of Massachusetts, have invented certain new and useful Improvements in Lens Grinding, of which the following is a specification. I

This invention relates to improvements in lens grinding and has for its principal object the provision of novel and improved means for accurately determining the thickness of a series of lenses while the same are being ground.

A further object of the present invention is the provision of a novel and improved form of variable gauge for grinding blocks which will automatically indicate the progblock embodying my improvements.

Figure II represents a vertical sectional view of the parts during the grinding operation. I

Figure III represents a plan view of one form of my invention.

Figure IV represents a similar view of a modified form thereof.

Figure V represents a gauge mechanism.

Figure VI represents a sectional view of a concave block embodying my improvements.

detail view of the In the drawings, in which similar characters of reference are employed to denote cor-v responding parts throughout the several o ,views, the numeral 1 designates the metal base or core portion of a lens block having the socket 2 for the actuating member 3, and having applied thereto the heavy pitch or similar material coat 4 in the usual manner. This coat 4: is preferably molded to provide the upstanding portions 01' spots 5 of plano stock and,

to the angle of the upper face of the modifications in I also equal,

gauge member and the I to make its use possible,

Serial no. 363,925.

of proper height factorilyreceive the lenses 6 to be ground. It is to be understood that these lenses may be secured on thespots by slightly heating against the mathe lenses and pressing them terial 4:. It will be noted that in addition to the lens receiving spots 5 thereis provided on the material 4L the additional and configuration to satis? spot portion 7 which is adapted toreceive,

the gauge glass 8. This may be a single central spot, as illustrated in Figure III for. example, or there. may be a plurality of these spots 7 as is illustrated In any event it is to be noted that the portion 7 is tilted at an angle within place of conforming to or being a tangent 'of the curve of the lap. It is further to be noted that the gauge piece 8 is preferably formed therefore, corresponds in angle portion 7 I would call particular attention .for an understanding of the underlying principles. of my invention, to Figure II, in whichI haveshown the line'A B as extendingfrom the center of curvature of the grinding lap 9 at the position then occupied by said lap,

' in Figure IV.

which is at the supposedv completion of the grinding operation, to the surface of the lens which has been ground, and that I have, also shown the line A-C extending from the same center to the point of intersection of the center of the upper face of the gauge piece 8 and the grinding surface of the lap 9, and by comparison it will be found that the lines AB and A-C are of equal length. It will also be found that the length of the line A-Dorfrom the center A to the center ofthe outer surface of the lensreceiving spot 5 and the length of theflline A-,E or distance from the center A to the surface of the gauge receiving spot 7 are while the thickness of the j'gauge the same thickness as that of the piece 8' is the, completion of the grinding lenses ,6 at operation. o- I will nowexplain briefly the use of my manner in' whic several points above enumerated cooperate In the grinding of lenses the block '1 having been prepared as shown in FigureI with the series of lenses 6-to be ground in position and the'gauge h themember 8 also in its position, the grinding tool or lap 9 is placed in operative relation to the block and the parts suitably shifted to produce the grinding etlect. As tie grinding starts on the several lenses 6 it will also start on the upper or right hand corner of the gauge member 8 as located in Figure l and will start grinding down this gauge member, which on account of its flat upper l on mation will be ground away faster at the sides than at the center leaving on the upper faceof the gauge a hali moon cleared effect with an adjacent ground glass por on, as should bereadily understood by reference to Figures III and IV, this half moon gradu ally creeping across the face of the gauge member 8 as the lap moves downward through grinding away of the material of the gauge member and the so all lenses. In view of the'fact that the height of the spot 7 at the center line or graduation thereon is the same as the height or distance from center of the several lens receiving spots, it will at once be seen that a spherical grimling tool grinding away equally the scverallenscs and the material of the gauge member 8 on the spot 7 will approach equally the center points or" the several lens and gauge receiving spots and that, therefore, the center thickness of each of the lenses will be the same as the center point thickness of the gauge piece. @n account of the fact that'the gauge'piece is in the form oi a narrow fiat niemberresting'on'a fiat surface it is possible for theeye'to readily recognize or measure the center'thickness of the gauge piece and thus for the grinder to determine the center thickness to which each lens has been ground, and thus to gauge just how far the grinding or roughing process should continue and how long the line grinding, in order to produce lenses to an accurate center thickness standand. An aditional advantage is gained, however, when the thickness of the gauge piece employed is the same asthe center thickness which it is desired to have on the finished lens. This is due to the fact that if the finished center thickness is the same as the thickness of the gauge piece then at the commencement ofthe operation the combined height of the spot and glass will be just the proper height so that the upper corner of the gauge member and the lenses will oe ground away simultaneously bringing the higher side of the gauge piece down to the prescribed height, while when the grinding o1 the'lenses has reached the point at which it has been determined the grinding should be stopped, in place of'the operator having to gauge by eye the thickness he need merely glance at the top of the gauge, piece, when if the back "of the half moon arc of grinding is found to -jbefo'n line with the center line designation 10 indicating the point E which haspref-er- @1919 been molded on the spot 7, he will know all of which I that the grinding operation should cease. If, however, it is desired to produce extra thin lenses suitable aditional designations ll may be provided on the face of the spot and the grinding continued until the half moon reaches any one of these, it being understood that the grinding on the surface of the gauge member will progress much more rapidly laterally than in vertical depth due to the slight relative angle at which the same is supported, with the result that the designations 11 may for example under some conditions be a millimeter apart but will indicate but one-tenth of a millimeter thickness variation on the lenses.

In Figure IV, I have shown a slightly different form of my invention in which in place of employing a single central gauge member the central space is occupied by a lens to be ground, and I have shown three small gauge and lens receiving spots disposed intermediate positions on'the block, this having the additional advantage that it enables the grinder to check the gauge pieces one against the other and determine whether there is undue or excessive grinding at one side of the block as respects the other.

igure Vl illlltI-ltlitbGS the principles but embodied in a concave in place of a conveX block, the general operation, however, being the same.

From the foregoing description taken in connection wi h the a'ccoinpanyin drawings it is believed the generic principles of my invention and one method of carrying'the same into effect will be readily understood, although it will be appreciated that various arrangements oi the gauge member other than those shown in the drawings'may be employed, and that while for convenience I have made use or" the half moon line of demarcation between ground and unground surfaces for determining when thegrinding operation has been completed, that the same result could be secured by the eye of a trained operator ls-iterally considering the gauge glass by applying a suitable gaugeto the spot and glass, r numerous other ways, consider within the purview of my invention so far may bevcovered by the appended claims.

I claim:

11 seats for-med having a plurality of le s thereonand a thickness gauge on theblock adjacent the seats for the lenses to be ground.

2. ln lens grinding, a block formed to receive a series of lenses for simultaneous grinding, thickness gauge memberzmounted on the block for grinding with the lenses and means cooperating with the gauge mem-' her for indicating the proper point'at which to stop the grinding operation.

'3. A lens block having lens receiving 1. In lens grinding, a lens receiving block seats, a gauge member arranged adjacent said seats and tilted with respect to the block.

4. A lens block comprising a base portion and a moldable covering therefor having portions molded into lens receiving spots and an integrally molded gauge receivlng 5. A lens block comprising a base portion and a moldable covering therefor having portions molded into lens receiving spots and an integrally spot, a gauge on said spot, sa1d gauge rece1ving spot having designations formed thereon cooperating with the gauge to indicate the progress of the grinding operation.

6. A lens block including lens receiving portions and a tilted gauge seat, said gauge seat having a fiat upper surface, and a gauge in the form of a flat glass plate secured on said surface and projecting into the path of operation of the grinding lap.

7 A lens block including lens receiving portions and a tilted gauge seat, said gauge seat having a fiat upper surface, a gauge in the form of a flat glass plate secured on said surface and projecting into the path of operation of the grinding lap whereby the gauge member will be ground away with the lenses, and means for measuring the trans verse grinding of the surface of the gauge.

8. The combination with a lens block hav- 1 molded gauge receiving ing lens receiving formed on the block having portions of greater and portions of less height than the height of the centers of the lens receiving 9. The combination with a lens block having lens receiving portions and a tilted seat formed on the block having portions of greater and portions of less height than portions of a tilted seat the height of the centers of the lens receiv-- 5 ing portions of the mounted on the seat projecting onto the tool, and means on limit to which'the surface of the gauge should be ground. 7

10 A curved lens block having a plurality of lens receiving spots whose centers'are the block, a gauge glass and having a portion path of the grinding same predetermined distance from the center of curvature of the block and having a gauge receiving spot and a gauge on the gauge receiving spot indicating the point on' the seat indicating the that spot corresponding in center distance I with the centers of the lens receiving spots. In testimony whereof I have afiixed my signature, in presence of two witnesses.

v GILBERT S. DEY.

Witnesses:

ESTHER M. LAFLER, Arron G. HASKELL. 

